1. P2MP MS-PW setup leaf initiated LDP-based solution draft-jounay-pwe3-leaf-initiated-p2mp-pw-02.txt
78th IETF Meeting - Maastricht
27th, July 2010
Frederic Jounay, Jean-Louis Le Roux, Philippe Niger
(France Telecom Orange)
Yuji Kamite
(NTT Communications)
Lizhong Jin
(ZTE)

2. P2MP-PW Background Requirements work Encapsulation draft
draft-ietf-pwe3-p2mp-pw-requirements and draft-ietf-l2vpn-vpms-frmwk- requirements ready for LC?
Encapsulation draft
draft-raggarwa-pwe3-p2mp-pw-encaps-01 ready for WG doc adoption?
BGP based solution
draft-raggarwa-l2vpn-p2mp-pw-03 ready for WG doc adoption?
LDP based solution
draft-ietf-pwe3-p2mp-pw-00 (P2MP SS-PW) (root-initiated)
draft-jounay-pwe3-leaf-initiated-p2mp-pw-02 (P2MP MS-PW)

3. What is covered so far? Root Initiated Leaf Initiated P2MP SS-PW
draft-ietf-pwe3-p2mp-pw-00
draft-jounay-pwe3-leaf-initiated-p2mp-pw-02
Root Initiated
Leaf Initiated
P2MP PW over P2MP LSP PW Upstream Label Assignment
PW segment over P2P LSP PW Downstream Label Assignment
P2MP SS-PW
P2MP MS-PW
Leaf initiated
Root PE
P router
Switching Point
(for MS-PW)
P2MP LSP
Leaf PE
P2MP PW
Switching PE
Root initiated
Next Step?
Dynamic P2MP MS-PW / P2MP LSP

4. Reference Model
P2MP MS-PW is composed of PW segments stitched at S-PE (PW replication)
CE2
leaf
P2P PSN Tunnel
(e.g. LDP or RSVP-TE)
P2P PW Segment
CE3
CE4 AC
CE5
CE6
CE1
root
CE7
Root T-PE
Ingress node
S-PE
Transit node
Leaf T-PE
Egress node

5. P2MP PW FEC Element The P2MP PW FEC uniquely identifies the PW tree
P2MP PW FEC Element defined in draft-ietf-pwe3-p2mp-pw-00
AGI (no change, used for VPNid, e.g. VPMS, VPLS), 4bytes
SAII (no change, P2MP PW source address)
P2MP PW (0x82) C
PW Type
PW Length
AGI Type
Length
AGI value
AII Type
Length
SAII value

6. LDP considerations for P2MP MS-PW
This draft defines the LDP procedure to setup a P2MP MS-PW in the same manner as defined with P2MP LSP (MLDP)
P2MP FEC (MLDP LSP) => P2MP PW FEC (T-LDP PW)
draft-ietf-mpls-ldp-p2mp-10
LDP Targeted Hellos
LDP session using the Extended Discovery mechanism described in [RFC 5036]. For setting up and maintaining pseudowires, each FEC TLV MUST contain exactly one FEC element.
LDP Capability
2 functions behind the "P2MP PW capa" in draft-ietf-pwe3-p2mp-pw upstream label assignment + PW status
Here only PW status required (no negotiation process as RFC4447)
Proposal to separate capability / function
LDP PW labels
Downstream assigned labels
Only unidirectionnal P2MP MS-PW addressed
(next version will describe the extension for bidirectionnal P2MP MS-PW)

7. P2MP MS-PW Configuration
1\ P2MP PW FEC configuration at root T-PE (e.g. [VPN (i.e. AGI), AII1])
2\ Leaf T-PE needs to know the P2MP PW FEC to be able to join the PW tree
leaf
CE2
PW tree [VPN, AII1]
PW tree [VPN, AII1]
CE3
CE4 AC
PW tree [VPN, AII1]
CE5
CE6
CE1
PW tree [VPN, AII1]
root
AII1
PW tree [VPN, AII1]
CE7

8. Signaling Procedures for P2MP MS-PW
3\ Leaf-initiated LDP signaling
S-PE installs a forwarding state in its PWtolabel bindings table and sends a label Map to the upstream PE (selection based on PW table)
LDP Label Map (FEC[SAII1, VPN], dLx)
4\ Leaf grafting/pruning
if existing state, just add/remove the outgoing i/f in the table (LDP Map not sent upstream)
leaf
CE2
PW tree [VPN, AII1]
PW tree [VPN, AII1]
CE3
CE4
PW tree [VPN, AII1] AC
CE5
PW tree [VPN, AII1]
CE6
CE1
PW tree [VPN, AII1]
root
AII1
PW tree [VPN, AII1]
CE7
PW tree [VPN, AII1]

9. Next Steps Leaf-initiated T-LDP for P2MP MS-PW setup
 Straightforward solution since based on existing MLDP procedures
Open issues
LDP Capability
One P2MP PW capability (upstream label assignment + PW status) or
One capability per function
PW status capability
Upstream label assignment (already defined)
Use of S-PE TLV to allow the root T-PE to discover the topology (LDP notification, VCCV, …)
Next steps
Add missing pieces for Optional bidirectional P2MP MS-PW and/or MP2MP MS-PW?
Need for WG feedback